1. Field of the Invention
The present invention relates to an obstacle-removing device for a guided vehicle to remove obstacles on exclusive guideway, particularly to a device to remove fallen snow, a massive amount of fallen leaves or fallen sand, and in some cases, dead animals such as crabs, frogs, etc., accumulated or lying on the guideway, with increased efficiency and without breakage of the device.
2. Description of the Related Art
Recent years, a medium capacity transit system, one of so-called new transit systems, in which guided vehicles equipped with rubber tires travel along exclusive guideway, has become widespread. In some cases the vehicle is equipped with guide wheels for guiding the vehicle along the guideway sometimes it happens that obstacles such as fallen snow, a massive amount of fallen leaves or fallen sand, and dead animals such as crabs, frogs, etc. lying on the exclusive guideway obstruct the passage of the guided vehicle, and the obstacles must be removed by the running vehicle itself.
For example, a snowplow attachment for a vehicle is disclosed in patent literature 1(Japanese Laid-Open Patent Application No. 2000-120037). The snowplow attachment will be attached to both the front and rear ends of a multiple-car vehicle. A supporting frame is provided to the vehicle in the front of front wheels and in the rear of rear wheels. A left and right snowplow are attached to each of the supporting frames respectively such that the snow-pushing brush of each of the left and right plows is skewed to face the left and right running surfaces of the exclusive guideway at an angle. A lifting/lowering device for lifting the plow to a retracted position and to lower the same to a snow removing position is mounted to the supporting frame. The plow is lowered so that the bottom edge of the snow-pushing brush contacts the running surface of the guideway when the plow is lowered to the snow removing position.
With the snowplow disclosed in the patent literature 1, the snow accumulating ahead of the vehicle is removed toward both sides of the guideway without leaving snow on the running surface by allowing the snow-pushing brush of the plow to contact the running surface of the guideway, thereby preventing occurrence of wheel slip.
The snowplow attached to the front of the vehicle in running direction thereof is lowered to the snow removing position, and the snowplow positioned to the rear of the vehicle in running state is lifted to a retracted position. Pushing out the snow accumulated on the running surface to both sides of the running surface is difficult to perform only with the brush as the snow does not slide smoothly toward both sides disturbed by the rough surface of the brushes, so a snow push-out plate is provided in front of each snow-pushing brush in order to push out the snow smoothly to both sides of the running surface. As material of the snow-pushing brush is desired such a material having sufficient rigidity and property of being not easily adhere to with snow, and a bamboo brush has long been used as most suitable one. Recent years, a brush made of synthetic resin is used.
A dual mode maintenance truck for performing various maintenance operations such as renewal of overhead catenary, repairing of pantographs, renewal of electric poles, etc. in railroad track has been proposed for the purpose of impelling laborsaving, promotion of efficiency, and enhancement of safety by improving working procedure. As two kinds of track gauges, i.e. standard-gauge (1.435 mm width) and narrow-gauge (1.067 mm width) are used in Japan, a running mechanism for a dual mode maintenance truck which can be changed over quickly and safely from using on the narrow-gauge railway to using on the standard-gauge railway and vice versa is provided in Japan.
However, with the running mechanism for a dual mode vehicle, when running on a narrow-gauge railway in winter season and removal of snow on the rails was already performed by an obstacle-removing device of another train, the snow removed from the surfaces of the rails and accumulated outside the rails forming mound of snow and ice interferes with the outside rear tired wheels for running on standard-gauge railways, and the dual mode truck can not be allowed to run for concern of occurrence of derailment. Further, when freezing occurred on surfaces of the rails due to very low temperature, slipping of the wheels contacting the surfaces of the rails, particularly rear tired wheels which are driving wheels occurs and smooth and safe running of the truck is obstructed. Therefore, the variety of maintenance operations in railways cannot be performed efficiently under such a condition as mentioned above.
To cope with this, a running mechanism for a dual mode vehicle is disclosed in patent literature 2 (Japanese Laid-Open Patent Application No. 10-203360). The running mechanism is composed such that: a snow removing device consisting of a horizontal auger having a spiral blade for removing snow and a motor for rotating the auger, an ice removing device consisting of a rotary brush and a motor for rotating the brush, are attached at the left and right of the front of the vehicle so that they can be lifted together; and an ice removing device is provided to remove the ice on the railways by blasting warm exhaust gas from the engine of the vehicle on to the surfaces of the railways.
However, with the snow removing device disclosed in the patent literature 1, the brush is pushed on to the concrete running surface so that the bristles of the brush are bent when removing snow, so the bristles tend to become loose and wear in a short time of use. Further, the guideway joint gaps become large in wintertime due to contraction of the guideway viaduct, and the bristles of the brush drops into the joint gap to be broken there. Further, it may occur that fallen snow adheres to the brush lifting/lowering mechanism and the spring for lifting the brush freezes there, resulting in the brush cannot be retracted.
On the other hand, when the fallen snow is removed to both sides of the vehicle by each of the left and right snowplows skewed to face the left and right running surface of the exclusive guideway at an angle, the snow swept toward both sides of the guideway accumulates in both sides of the guideway. When the amount of the accumulated snow increases, apart of the accumulated snow returns onto the running surface of the guideway on which the tired wheels tread on, because the both side spaces are restricted by the sidewalls of the guideway and not so large.
The snow returned onto the running surface of the guideway on which the wheels tread is formed into a compressed snow layer. Therefore, the running surface rises up and friction between the wheel and running surface decreases, and stable traveling of the vehicle becomes impossible.
When relatively a hard snow layer is formed on the running surface, it cannot be removed by the brush of the snowplow.
Further, there may occur a problem that the snow thrown up by the brush adheres to the brush lifting mechanism causing failure of the mechanism or that the thrown up snow falls on the running surface on which the tired wheels tread and forms a compressed snow layer.
The dual mode maintenance truck disclosed in the patent literature 2 is equipped with a left and right snow removing devices, each comprises a snow removing device consisting of a horizontal auger to remove snow and a motor for rotating the auger, an ice removing device consisting of a rotary brush and a motor for rotating the brush, and an ice removing device to remove the ice on the railways by blasting warm exhaust gas from the engine of the truck on to the surfaces of the railways, so the device becomes fairly a large scaled one and fairly large manufacturing cost is required.